Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 160343
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1143 PM EDT MON SEP 15 2014

.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE WILL MOVE EAST ACROSS THE OHIO RIVER
VALLEY TONIGHT BEFORE SLIDING OFF THE DELAWARE COAST DURING THE
MIDDAY HOURS TUESDAY. THIS LOW...WILL COMBINE WITH A DISTURBANCE
ALOFT TO BRING NUMEROUS SHOWERS TO NORTHERN PENN OVERNIGHT...WITH
SHOWERS OF THE MORE SCATTERED VARIETY OVER SOUTHERN PENN. THE
REST OF THIS WEEK WILL BE MAINLY DRY AS HIGH PRESSURE BRINGS
PLENTY OF SUNSHINE AND AND SLIGHTLY BELOW NORMAL TEMPERATURES TO
THE AREA.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THICKENING/LAYERED CLOUDS WILL CONTINUE TO SPREAD EAST ACROSS THE
REGION OVERNIGHT.

WEAK LOW PRESSURE OVER THE LOWER OHIO VALLEY /AND NEAR THE NOSE
OF A SLIGHTLY ANOMALOUS...SWRLY LLJ/ WILL SLIDE JUST TO THE SOUTH
OF THE STATE OVERNIGHT...WHILE BANDS OF 850-700 MB FGEN FORCING
/BENEATH THE RIGHT ENTRANCE REGION OF A 115 KT JET OVER SRN
ONTARIO/ MOVES ACROSS CENTRAL AND NRN PENN.

A LARGE AREA OF LIGHT TO MDT SHOWERS /COVERING MUCH OF LAKE ERIE
AND NRN OHIO AT 02Z/ WILL SHIFT EAST THROUGH THE OVERNIGHT HOURS
AND TARGET MAINLY THE NORTHERN THIRD TO HALF OF THE STATE.

15Z AND 21Z SREF AND 18Z OPERATIONAL NAM AND GFS INDICATE BASIN
AVERAGE QPF AMOUNTS OF 2-3 TENTHS ACROSS THE NRN TIER COUNTIES OF
PENN. EC ENSEMBLES ALSO IMPLY QUITE A SHARP GRADIENT IN POPS
FURTHER SOUTH ACROSS THE CWA - BETWEEN 1-80 AND I-70/76.

HOURLY AND OVERNIGHT LOW TEMPS LOOK IN PRETTY GOOD SHAPE WITH MINS
RANGING FROM 45-50F ACROSS THE NRN AND WRN MTNS...TO THE LOWER AND
MID 50S ELSEWHERE.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
COLD FRONT WILL BE MOVING ACROSS THE AREA VERY FAST TUESDAY
MORNING. ANY LIGHT PRECIP AFTER 12Z TUESDAY SHOULD BE CONFINED
ACROSS THE REGION JUST TO THE EAST OF THE SUSQ MAINSTEM. SKIES
WILL CLEAR OUT QUICKLY BY NOON IN MOST PLACES...THOUGH SOME
BRIEFLY BKN...FLAT STRATO CU ARE POSSIBLE DURING THE MIDDAY AND
AFTERNOON HOURS ACROSS THE NRN TIER OF PENN.

HEIGHTS STAY FAIRLY HIGH...SO NOT SEEING MUCH LAKE EFFECT
ACTIVITY. SOME CLOUDS EARLY ON.

WIND WILL LIKELY KICK UP SOME.

MAIN CONCERN WILL BE POTENTIAL FOR FROST AND FREEZING
TEMPS ACROSS THE NORTH TUE NIGHT. MAV NUMBERS HAVE BFD
BELOW 32. CLEAR SKIES AND LIGHT WINDS...ALONG WITH
HIGH HEIGHTS AND LOW DEWPOINTS/PW VALUES SUPPORT SOME
POTENTIAL FOR FROST ETC. STILL A WAYS OUT...LATER SHIFTS CAN
MONITOR AND ISSUE FLAGS AS NEEDED.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
BY WED...SURFACE HIGH PRESSURE OVER OHIO VALLEY WITH DRIER COOLER
NORTHWEST FLOW IN LOWER LEVELS. THERE MAY BE SOME CLOUDS LINGERING
OVER HIGHER TERRAIN UNDER SUBSIDENCE INVERSION EARLY...BUT
CENTRAL PA SHOULD SEE GOOD DEAL OF SUNSHINE OVERALL. HIGHS WILL BE
ABOUT 5F BELOW NORMAL.

TROUGH ALOFT SHARPENS OVER QUEBEC WED NIGHT/THU...PUSHING A WEAK
FRONTAL BOUNDARY SOUTH TOWARD PA ON THU. THIS FRONT WILL CONTINUE
TO WEAKEN AS IT EDGES SOUTHWARD...BUT A WEAK SHORTWAVE WILL SLIDE
OVERHEAD FROM THE MIDWEST. THIS WILL BRING AN INCREASE IN CLOUDS
COVER ALONG WITH JUST A CHANCE FOR A SPRINKLE. NORTHERN PA WILL
GET A REINFORCING SHOT OF COOLER AIR...KEEPING HIGHS IN THE UPPER
50S TO LOWER 60S.

HIGH PRESSURE THEN BUILDS ACROSS THE GREAT LAKES INTO A 1030MB
HIGH OVER NEW ENGLAND BY FRI...BRINGING A PERIOD OF QUIET WEATHER
AND UNSEASONABLY COOL TEMPERATURES. MORNING LOWS IN THE 30S ARE
LIKELY THU NIGHT IF SKIES CLEAR OUT AS ANTICIPATED. HIGHS ON FRI
WILL BE MAINLY IN THE 60S AS NW FLOW CONTINUES.

RETURN FLOW BEGINS WEAKLY FRI NIGHT...TAKING A LITTLE OF THE BITE
OUT OF OVERNIGHT LOWS /THOUGH STILL CHILLY WITH READINGS MAINLY IN
THE 40S/. BUT THIS WILL BEGIN A WARMING TREND FOR THE WEEKEND.
TEMPS SAT INTO SUN WILL BE 5-8F WARMER THAN FRI...WITH HIGHS
APPROACHING 80F IN THE SE. LOWS WILL BE NOTICEABLY MILDER AS WELL
AS LOW LEVEL MOISTURE INCREASES IN STRENGTHENING SW FLOW.

HEADING INTO SUNDAY...DEEPENING LOW CENTERED WELL TO OUR NORTH
AS A TROUGH AXIS ROTATES THROUGH THE GREAT LAKES WILL BRING PLENTY
OF CLOUDS AND A CHANCE FOR SHOWERS. MODELS STILL SHOWING LARGE
DIFFERENCES ON EVOLUTION OF THIS SYSTEM...WITH GFS MORE
PROGRESSIVE AND ECMWF ACTUALLY BRINGING A SECOND WAVE AROUND THE
BACKSIDE OF THE TROUGH AND DEVELOPING A STUBBORN CLOSED UPPER LOW
OVER THE REGION. FOR NOW WILL SPLIT THE DIFFERENCE AND HOLD ON TO
MENTION OF SHOWERS INTO MON ALONG WITH ANOTHER SHOT OF COOLER AIR
AND SEE HOW THIS PLAYS OUT OVER NEXT COUPLE OF DAYS.

&&

.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
AREA OF SHOWERS MOVING INTO NWRN PA ATTM. ARE FAIRLY LIGHT BUT
WILL LEAD TO SOME GRADUAL REDUCTIONS ESP ACROSS NWRN AIRFIELDS
EARLY THEN CENTRAL AND SRN OVERNIGHT.

CONDITIONS SHOULD BECOME VFR BY MID TO LATE MORNING ON
TUESDAY...AS THE COLD FRONT MOVES EAST OF THE AREA. IT WILL BE
BREEZY AT TIMES ON TUE.

SOME POTENTIAL FOR FOG TUESDAY NIGHT...AS HIGH PRESSURE
BUILDS OVER THE AREA.

MAINLY DRY CONDITIONS THE REST OF THE WEEK...AS HIGH PRESSURE
PREVAILS.

OUTLOOK...

WED-SAT...MAINLY VFR CONDITIONS.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...LAMBERT/MARTIN
NEAR TERM...LAMBERT/MARTIN
SHORT TERM...LAMBERT
LONG TERM...RXR
AVIATION...GARTNER/MARTIN


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